When the Nazis invaded the Netherlands, they didn’t want to deal with the possibility of the Dutch tuning in foreign radio broadcasts. So in the spring of 1942, they simply confiscated all radio receivers.
Undaunted, Dutch radio enthusiasts simply went underground and constructed sets to listen to the BBC and Radio Boston to learn how the war was going. A number of interesting radios were described in the March 1947 issue of Radio Craft, in an article by one Mr. J. Maquerinck, who described sets built by himself and others.
The simplest, or course, was the venerable crystal set, such as the one shown here, constructed by one of the author’s friends. This set pulled in England quite well and was constructed in a wooden box. When the friend wanted to listen, he opened the box, hooked up an antenna and ground, and tuned in the BBC.
Another friend, who had in his possession a vacuum tube, constructed the simple one-tube set shown here. This friend had no variable capacitor, but the coil wound on an iron core provided adequate selectivity, and was sensitive enough to pull in England.
The author himself wanted to avoid the complication of an external antenna, which could be seen. He was fortunate enough to own a dual tube, which he was able to use in the circuit shown here as RF amplfier, grid-leak detector, and audio amplifier. To conceal the set, he hollowed out his telephone and built it inside the phone cabinet. His finger served as enough of an antenna to pull in the BBC on 200 kHz. The telephone’s ground connection served as the radio’s ground.
To avoid detection, he had the phone set up so that the dial had to be turned to 7 to power up the radio. As an added precaution, he placed above the radio the sign shown here, meaning “Take care, don’t use. Defective!” He noted that the loss of the telephone wasn’t much of a loss, since it had been out of order most of the time anyway.
This “real radio-telephone” was never discovered. In September 1944, the civilian population of the author’s town was evacuated. When he returned, everything else in the house had been stolen, but the receiver remained. I guess even Nazis were afraid of messing with the telephone company’s equipment.
The author was evacuated to the town of Aalten, population 10,000. The owner of the home in which the author resided had not previously owned a radio, but the town’s serviceman constructed a regenerative which used plug-in coils, one for 200 kHz and the other for 1000 kHz. The 200 kHz frequency was used to tune in the BBC, and 1000 kHz was the frequency of a station in a part of Holland that had already been liberated.
For another look at clandestine radio receivers used during the war, see our prior post on radios in occupied Guernsey.